Commit d7880812b3594d3c6dcbe3cfd71dabb17347d082
1 parent
c7788792a5
Exists in
smarc-l5.0.0_1.0.0-ga
and in
5 other branches
idle: Add the stack canary init to cpu_startup_entry()
Moving x86 to the generic idle implementation (commit 7d1a9417 "x86: Use generic idle loop") wreckaged the stack protector. I stupidly missed that boot_init_stack_canary() must be inlined from a function which never returns, but I put that call into arch_cpu_idle_prepare() which of course returns. I pondered to play tricks with arch_cpu_idle_prepare() first, but then I noticed, that the other archs which have implemented the stackprotector (ARM and SH) do not initialize the canary for the non-boot cpus. So I decided to move the boot_init_stack_canary() call into cpu_startup_entry() ifdeffed with an CONFIG_X86 for now. This #ifdef is just a temporary measure as I don't want to inflict the boot_init_stack_canary() call on ARM and SH that late in the cycle. I'll queue a patch for 3.11 which removes the #ifdef if the ARM/SH maintainers have no objection. Reported-by: Wouter van Kesteren <woutershep@gmail.com> Cc: x86@kernel.org Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Showing 2 changed files with 16 additions and 12 deletions Side-by-side Diff
arch/x86/kernel/process.c
... | ... | @@ -277,18 +277,6 @@ |
277 | 277 | } |
278 | 278 | #endif |
279 | 279 | |
280 | -void arch_cpu_idle_prepare(void) | |
281 | -{ | |
282 | - /* | |
283 | - * If we're the non-boot CPU, nothing set the stack canary up | |
284 | - * for us. CPU0 already has it initialized but no harm in | |
285 | - * doing it again. This is a good place for updating it, as | |
286 | - * we wont ever return from this function (so the invalid | |
287 | - * canaries already on the stack wont ever trigger). | |
288 | - */ | |
289 | - boot_init_stack_canary(); | |
290 | -} | |
291 | - | |
292 | 280 | void arch_cpu_idle_enter(void) |
293 | 281 | { |
294 | 282 | local_touch_nmi(); |
kernel/cpu/idle.c
... | ... | @@ -5,6 +5,7 @@ |
5 | 5 | #include <linux/cpu.h> |
6 | 6 | #include <linux/tick.h> |
7 | 7 | #include <linux/mm.h> |
8 | +#include <linux/stackprotector.h> | |
8 | 9 | |
9 | 10 | #include <asm/tlb.h> |
10 | 11 | |
... | ... | @@ -112,6 +113,21 @@ |
112 | 113 | |
113 | 114 | void cpu_startup_entry(enum cpuhp_state state) |
114 | 115 | { |
116 | + /* | |
117 | + * This #ifdef needs to die, but it's too late in the cycle to | |
118 | + * make this generic (arm and sh have never invoked the canary | |
119 | + * init for the non boot cpus!). Will be fixed in 3.11 | |
120 | + */ | |
121 | +#ifdef CONFIG_X86 | |
122 | + /* | |
123 | + * If we're the non-boot CPU, nothing set the stack canary up | |
124 | + * for us. The boot CPU already has it initialized but no harm | |
125 | + * in doing it again. This is a good place for updating it, as | |
126 | + * we wont ever return from this function (so the invalid | |
127 | + * canaries already on the stack wont ever trigger). | |
128 | + */ | |
129 | + boot_init_stack_canary(); | |
130 | +#endif | |
115 | 131 | current_set_polling(); |
116 | 132 | arch_cpu_idle_prepare(); |
117 | 133 | cpu_idle_loop(); |